Commit dd277622 authored by Sami Tolvanen's avatar Sami Tolvanen Committed by Kees Cook
Browse files

kbuild: lto: merge module sections 



LLD always splits sections with LTO, which increases module sizes. This
change adds linker script rules to merge the split sections in the final
module.

Suggested-by: default avatarNick Desaulniers <ndesaulniers@google.com>
Signed-off-by: default avatarSami Tolvanen <samitolvanen@google.com>
Reviewed-by: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20201211184633.3213045-6-samitolvanen@google.com
parent 22d429e7

scripts/module.lds.S

+24 −0
Original line number Diff line number Diff line
@@ -23,6 +23,30 @@ SECTIONS { 
	.init_array		0 : ALIGN(8) { *(SORT(.init_array.*)) *(.init_array) }



	__jump_table		0 : ALIGN(8) { KEEP(*(__jump_table)) }



	__patchable_function_entries : { *(__patchable_function_entries) }



	/*

	 * With CONFIG_LTO_CLANG, LLD always enables -fdata-sections and

	 * -ffunction-sections, which increases the size of the final module.

	 * Merge the split sections in the final binary.

	 */

	.bss : {

		*(.bss .bss.[0-9a-zA-Z_]*)

		*(.bss..L*)

	}



	.data : {

		*(.data .data.[0-9a-zA-Z_]*)

		*(.data..L*)

	}



	.rodata : {

		*(.rodata .rodata.[0-9a-zA-Z_]*)

		*(.rodata..L*)

	}



	.text : { *(.text .text.[0-9a-zA-Z_]*) }

}



/* bring in arch-specific sections */